Report same error-code on windows for all not-found cases.

runtime/bin/directory_win.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "platform/globals.h"
 #if defined(TARGET_OS_WINDOWS)
 
 #include "bin/directory.h"
 #include "bin/file.h"
 
@@ skipping 412 matching lines @@
 }
 
 
 bool Directory::Delete(const char* dir_name, bool recursive) {
   bool result = false;
   const wchar_t* system_dir_name = StringUtils::Utf8ToWide(dir_name);
   if (!recursive) {
     if (File::GetType(dir_name, true) == File::kIsDirectory) {
       result = (RemoveDirectoryW(system_dir_name) != 0);
     } else {
-      SetLastError(ERROR_DIRECTORY);
+      SetLastError(ERROR_FILE_NOT_FOUND);
     }
   } else {
     PathBuffer path;
     if (path.Add(system_dir_name)) {
       result = DeleteRecursively(&path);
     }
   }
   free(const_cast<wchar_t*>(system_dir_name));
   return result;
 }
@@ skipping 14 matching lines @@
   }
   DWORD flags = MOVEFILE_WRITE_THROUGH;
   int move_status =
       MoveFileExW(system_path, system_new_path, flags);
   free(const_cast<wchar_t*>(system_path));
   free(const_cast<wchar_t*>(system_new_path));
   return (move_status != 0);
 }
 
 #endif  // defined(TARGET_OS_WINDOWS)